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<div class="refentry" title="Version Information">
<a name="cairo-version-info"></a><div class="titlepage"></div>
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<td valign="top">
<h2><span class="refentrytitle"><a name="cairo-version-info.top_of_page"></a>Version Information</span></h2>
<p>Version Information — Compile-time and run-time version checks.</p>
</td>
<td valign="top" align="right"></td>
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<div class="refsynopsisdiv" title="Synopsis">
<a name="cairo-version-info.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION--CAPS" title="CAIRO_VERSION">CAIRO_VERSION</a>
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-MAJOR--CAPS" title="CAIRO_VERSION_MAJOR">CAIRO_VERSION_MAJOR</a>
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-MINOR--CAPS" title="CAIRO_VERSION_MINOR">CAIRO_VERSION_MINOR</a>
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-MICRO--CAPS" title="CAIRO_VERSION_MICRO">CAIRO_VERSION_MICRO</a>
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-STRING--CAPS" title="CAIRO_VERSION_STRING">CAIRO_VERSION_STRING</a>
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-ENCODE--CAPS" title="CAIRO_VERSION_ENCODE()">CAIRO_VERSION_ENCODE</a>                (major, minor, micro)
#define             <a class="link" href="cairo-version-info.html#CAIRO-VERSION-STRINGIZE--CAPS" title="CAIRO_VERSION_STRINGIZE()">CAIRO_VERSION_STRINGIZE</a>             (major, minor, micro)
int                 <a class="link" href="cairo-version-info.html#cairo-version" title="cairo_version ()">cairo_version</a>                       (void);
const char *        <a class="link" href="cairo-version-info.html#cairo-version-string" title="cairo_version_string ()">cairo_version_string</a>                (void);
</pre>
</div>
<div class="refsect1" title="Description">
<a name="cairo-version-info.description"></a><h2>Description</h2>
<p>
Cairo has a three-part version number scheme. In this scheme, we use
even vs. odd numbers to distinguish fixed points in the software
vs. in-progress development, (such as from git instead of a tar file,
or as a "snapshot" tar file as opposed to a "release" tar file).
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
 _____ Major. Always 1, until we invent a new scheme.
/  ___ Minor. Even/Odd = Release/Snapshot (tar files) or Branch/Head (git)
| /  _ Micro. Even/Odd = Tar-file/git
| | /
1.0.0
</pre></div>
<p>
</p>
<p>
Here are a few examples of versions that one might see.
</p>
<div class="informalexample"><pre class="programlisting">
Releases
--------
1.0.0 - A major release
1.0.2 - A subsequent maintenance release
1.2.0 - Another major release
Snapshots
---------
1.1.2 - A snapshot (working toward the 1.2.0 release)
In-progress development (eg. from git)
--------------------------------------
1.0.1 - Development on a maintenance branch (toward 1.0.2 release)
1.1.1 - Development on head (toward 1.1.2 snapshot and 1.2.0 release)
</pre></div>
<p>
</p>
<div class="refsect2" title="Compatibility">
<a name="id2663590"></a><h3>Compatibility</h3>
<p>
The API/ABI compatibility guarantees for various versions are as
follows. First, let's assume some cairo-using application code that is
successfully using the API/ABI "from" one version of cairo. Then let's
ask the question whether this same code can be moved "to" the API/ABI
of another version of cairo.
</p>
<p>
Moving from a release to any later version (release, snapshot,
development) is always guaranteed to provide compatibility.
</p>
<p>
Moving from a snapshot to any later version is not guaranteed to
provide compatibility, since snapshots may introduce new API that ends
up being removed before the next release.
</p>
<p>
Moving from an in-development version (odd micro component) to any
later version is not guaranteed to provide compatibility. In fact,
there's not even a guarantee that the code will even continue to work
with the same in-development version number. This is because these
numbers don't correspond to any fixed state of the software, but
rather the many states between snapshots and releases.
</p>
</div>
<hr>
<div class="refsect2" title="Examining the version">
<a name="id2663629"></a><h3>Examining the version</h3>
<p>
Cairo provides the ability to examine the version at either
compile-time or run-time and in both a human-readable form as well as
an encoded form suitable for direct comparison. Cairo also provides the
macro <a class="link" href="cairo-version-info.html#CAIRO-VERSION-ENCODE--CAPS" title="CAIRO_VERSION_ENCODE()"><code class="function">CAIRO_VERSION_ENCODE()</code></a> to perform the encoding.
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
Compile-time
------------
CAIRO_VERSION_STRING	Human-readable
CAIRO_VERSION		Encoded, suitable for comparison
Run-time
--------
cairo_version_string()	Human-readable
cairo_version()		Encoded, suitable for comparison
</pre></div>
<p>
</p>
<p>
For example, checking that the cairo version is greater than or equal
to 1.0.0 could be achieved at compile-time or run-time as follows:
</p>
<div class="informalexample"><pre class="programlisting">
##if CAIRO_VERSION &gt;= CAIRO_VERSION_ENCODE(1, 0, 0)
printf ("Compiling with suitable cairo version: %s\n", %CAIRO_VERSION_STRING);
##endif
if (cairo_version() &gt;= CAIRO_VERSION_ENCODE(1, 0, 0))
    printf ("Running with suitable cairo version: %s\n", cairo_version_string ());
</pre></div>
<p>
</p>
</div>
</div>
<div class="refsect1" title="Details">
<a name="cairo-version-info.details"></a><h2>Details</h2>
<div class="refsect2" title="CAIRO_VERSION">
<a name="CAIRO-VERSION--CAPS"></a><h3>CAIRO_VERSION</h3>
<pre class="programlisting">#define             CAIRO_VERSION</pre>
<p>
The version of cairo available at compile-time, encoded using
<a class="link" href="cairo-version-info.html#CAIRO-VERSION-ENCODE--CAPS" title="CAIRO_VERSION_ENCODE()"><code class="function">CAIRO_VERSION_ENCODE()</code></a>.
</p>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_MAJOR">
<a name="CAIRO-VERSION-MAJOR--CAPS"></a><h3>CAIRO_VERSION_MAJOR</h3>
<pre class="programlisting">#define CAIRO_VERSION_MAJOR USE_cairo_version_OR_cairo_version_string_INSTEAD
</pre>
<p>
The major component of the version of cairo available at compile-time.
</p>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_MINOR">
<a name="CAIRO-VERSION-MINOR--CAPS"></a><h3>CAIRO_VERSION_MINOR</h3>
<pre class="programlisting">#define CAIRO_VERSION_MINOR USE_cairo_version_OR_cairo_version_string_INSTEAD
</pre>
<p>
The minor component of the version of cairo available at compile-time.
</p>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_MICRO">
<a name="CAIRO-VERSION-MICRO--CAPS"></a><h3>CAIRO_VERSION_MICRO</h3>
<pre class="programlisting">#define CAIRO_VERSION_MICRO USE_cairo_version_OR_cairo_version_string_INSTEAD
</pre>
<p>
The micro component of the version of cairo available at compile-time.
</p>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_STRING">
<a name="CAIRO-VERSION-STRING--CAPS"></a><h3>CAIRO_VERSION_STRING</h3>
<pre class="programlisting">#define             CAIRO_VERSION_STRING</pre>
<p>
A human-readable string literal containing the version of cairo available
at compile-time, in the form of "X.Y.Z".
</p>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_ENCODE()">
<a name="CAIRO-VERSION-ENCODE--CAPS"></a><h3>CAIRO_VERSION_ENCODE()</h3>
<pre class="programlisting">#define             CAIRO_VERSION_ENCODE(major, minor, micro)</pre>
<p>
This macro encodes the given cairo version into an integer.  The numbers
returned by <a class="link" href="cairo-version-info.html#CAIRO-VERSION--CAPS" title="CAIRO_VERSION"><code class="literal">CAIRO_VERSION</code></a> and <a class="link" href="cairo-version-info.html#cairo-version" title="cairo_version ()"><code class="function">cairo_version()</code></a> are encoded using this macro.
Two encoded version numbers can be compared as integers.  The encoding ensures
that later versions compare greater than earlier versions.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>major</code></em> :</span></p></td>
<td>the major component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>minor</code></em> :</span></p></td>
<td>the minor component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>micro</code></em> :</span></p></td>
<td>the micro component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the encoded version.
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" title="CAIRO_VERSION_STRINGIZE()">
<a name="CAIRO-VERSION-STRINGIZE--CAPS"></a><h3>CAIRO_VERSION_STRINGIZE()</h3>
<pre class="programlisting">#define             CAIRO_VERSION_STRINGIZE(major, minor, micro)</pre>
<p>
This macro encodes the given cairo version into an string.  The numbers
returned by <a class="link" href="cairo-version-info.html#CAIRO-VERSION-STRING--CAPS" title="CAIRO_VERSION_STRING"><code class="literal">CAIRO_VERSION_STRING</code></a> and <a class="link" href="cairo-version-info.html#cairo-version-string" title="cairo_version_string ()"><code class="function">cairo_version_string()</code></a> are encoded using this macro.
The parameters to this macro must expand to numerical literals.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>major</code></em> :</span></p></td>
<td>the major component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>minor</code></em> :</span></p></td>
<td>the minor component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>micro</code></em> :</span></p></td>
<td>the micro component of the version number
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a string literal containing the version.
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 1.8</p>
</div>
<hr>
<div class="refsect2" title="cairo_version ()">
<a name="cairo-version"></a><h3>cairo_version ()</h3>
<pre class="programlisting">int                 cairo_version                       (void);</pre>
<p>
Returns the version of the cairo library encoded in a single
integer as per <a class="link" href="cairo-version-info.html#CAIRO-VERSION-ENCODE--CAPS" title="CAIRO_VERSION_ENCODE()"><code class="literal">CAIRO_VERSION_ENCODE</code></a>. The encoding ensures that
later versions compare greater than earlier versions.
</p>
<p>
A run-time comparison to check that cairo's version is greater than
or equal to version X.Y.Z could be performed as follows:
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
if (cairo_version() &gt;= CAIRO_VERSION_ENCODE(X,Y,Z)) {...}
</pre></div>
<p>
</p>
<p>
See also <a class="link" href="cairo-version-info.html#cairo-version-string" title="cairo_version_string ()"><code class="function">cairo_version_string()</code></a> as well as the compile-time
equivalents <a class="link" href="cairo-version-info.html#CAIRO-VERSION--CAPS" title="CAIRO_VERSION"><code class="literal">CAIRO_VERSION</code></a> and <a class="link" href="cairo-version-info.html#CAIRO-VERSION-STRING--CAPS" title="CAIRO_VERSION_STRING"><code class="literal">CAIRO_VERSION_STRING</code></a>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td> the encoded version.
</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2" title="cairo_version_string ()">
<a name="cairo-version-string"></a><h3>cairo_version_string ()</h3>
<pre class="programlisting">const char *        cairo_version_string                (void);</pre>
<p>
Returns the version of the cairo library as a human-readable string
of the form "X.Y.Z".
</p>
<p>
See also <a class="link" href="cairo-version-info.html#cairo-version" title="cairo_version ()"><code class="function">cairo_version()</code></a> as well as the compile-time equivalents
<a class="link" href="cairo-version-info.html#CAIRO-VERSION-STRING--CAPS" title="CAIRO_VERSION_STRING"><code class="literal">CAIRO_VERSION_STRING</code></a> and <a class="link" href="cairo-version-info.html#CAIRO-VERSION--CAPS" title="CAIRO_VERSION"><code class="literal">CAIRO_VERSION</code></a>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td> a string containing the version.
</td>
</tr></tbody>
</table></div>
</div>
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